The vaginal cervical stimulation (VCS) that female rats receive when a male intromits has dramatic effects on their subsequent sexual behavior. It has been hypothesized that these effects are a consequence of changes induced by VCS in the activity of estrogen and progestin receptor- containing neurons of the mediobasal hypothalamus (MBH) and preoptic area. Within the context sexual behavior, norepinephrine (NE) may play an important role in modulating the activity of these neurons because (a) NE is released in the MBH when females copulate and (b) noradrenergic antagonists disrupt female sexual behavior. The experiments in this proposal address this hypothesis by determining the following: (a) the effects that NE has on the various components of female sexual behavior, (b) whether or not estrogen receptor-containing neurons possess noradrenergic receptors, (c) whether or not noradrenergic antagonists affect the induction of Fos expression in estrogen receptor-containing neurons by VCS, and (d) whether or not hormone treatments that affect noradrenergic activity in the MBH affect the induction of Fos expression by VCS.